Configurable limits

When you're trying to determine your system's limits, you can get the
values of configurable limits, special
read-only variables that store system information.

Note:QNX Neutrino also supports configuration strings, which are similar
to, and frequently used in conjunction with, environment variables.
For more information, see the
Configuring Your Environment
chapter.

You can use the POSIX
getconf
utility to get the value of a configurable limit or a configuration string.
Since getconf is a POSIX utility, scripts that use it instead of
hard-coded QNX Neutrino-specific limits can adapt to other POSIX environments.

Some configurable limits are associated with a path; their names start with
_PC_.
When you get the value of these limits, you must provide the path (see
"Filesystem limits,"
below).
For example, to get the maximum length of the filename, type:

getconf _PC_NAME_MAX pathname

Other limits are associated with the entire system; their names start with
_SC_.
You don't have to provide a path when you get their values.
For example, to get the maximum number of files that a process can have
open, type:

getconf _SC_OPEN_MAX

In general, you can't change the value of the configurable limits—they're
called "configurable" because the system can set them.

The QNX Neutrino libraries provide various functions that you can use in a
program to work with configurable limits: